I have a synergy 2 unit and i am looking for a power amp. Problem i have is, i don't really want to drop £1200 on the synergy 50/50 as i am only using this for a small bedroom setup. I can buy a used Mesa 2:100 for £500 over here in the uk.

If you don't need stereo the Fryette Power Station works. Other options

Mooer Tube Engine 20 watts mono coming out in april cheap
VHT/Fryette 2/50/2 or 2/90/2
Randal RT 2 50 cool because one side can have el34's and 6L6 on the other.
Mesa 2/90 2:50 or 20/20
Peavey makes some cheap ones out there
Carvin TS 100 is affordable too
Marshall has some as well.

Plenty of options. Budget and needs will narrow it down for you._________________Synergy Syn2 with T/DLX and SLO modules
AXE FX XL for all fx and cab ir's as well.

I'm using a Power Station as well...has the added benefit of being able to record silently, still pushing Power Tubes and recording direct to DAW using IR's.

I haven't opened it up yet to hear how it sounds, i've mostly only been running on a Bogner 1x12 or direct at house volume. I also have a Peavey Classic 50/50 for stereo use when i get a chance to hook it all up in stereo._________________Synergy: Syn-2, SLO, Metroplex
Randall: JTM, Clean, Blackface
Egnater: EG2
Strymon Flint and Mobius, TC Triple Delay, JHS Andy Timmons, Kemper, Ventris, Koko Boost, Carl Martin AT Compressor, Proanalog MKIV Fuzz, Ibanez TS9dx